The Peak synthesis of the human placental hormones, placental lactogen (hPL) and chorionic gonadotropin (hCG) are expressed at different stages in pregnancy. This proposal is aimed toward understanding the mechanisms involved in regulating the production of (hCG) and (hPL) as a function of pregnancy. To study the detailed expression of these hormonal genes, we will clone complete copy double stranded cDNAs (or restriction fragments thereof) transcribed from partially purified hPL and hCG mRNAs. This should result in homogeneous probes which can be used for studying: (1) levels and turnover of the mRNA; (2) identification and processing of their corresponding transcripts, and (3) possible translational control mechanisms. The cloned probes will be used to ascertain whether or not the hCG genes are in the same chromosome and if so are they in close proximity. In addition, using in situ hybridization with the cDNA probes, we will attempt to elucidate the type of trophoblast responsible for the synthesis of the hormones. Efforts will be made to study post-translational modification of these hormones. Specifically, we will investigate the coupling of carbohydrate to the protein portions of the hCG subunits in the cell-free system. The studies will include attempts to understand the basis for specificity in the carbohydrate structure for secretory glycoproteins. We will also explore the possibility that the attachment of sugar plays a role in the differential secretion of the hCG subunits. It is believed that these studies will provide further information as to (a) the molecular mechanisms by which the synthesis of a specific placental protein is coupled to the gestational period and (b) the relationships of these phenomena in the normal induced states of placental function.